Weather Proofing

Weatherproofing is the process of applying a weather-proofer to a fabric soft top. After the hood is cleaned, it needs to be thoroughly dried.

Hydrophobic coatings are oil based water repellant coatings, and so they will not stick to anything that is wet.  It is also important to apply the coating somewhere that will stay dry until the coating has set because oil is lighter than water, so if it rains while the coating is wet, it can be affected.

Weather proofing coatings come as a clear liquid and can be sprayed on, we have found it is best to brush them in, thoroughly saturating the hood. 

Although weatherproof coatings will not damage paintwork or glass, it is often a good idea to mask off the roof, as the procedure can get a little messy. But if it does run onto the bodywork, just wipe it off.

What it means

Weather proofing is the overall process of protecting a soft top from the elements. On a fabric or mohair convertible roof it usually involves thoroughly cleaning away grit, algae and roof green, letting the roof dry, and then applying specialist proofers or protective coatings so rain beads and runs off more easily. In some cases it may also include treating seals and gutters so the whole roof system copes better with water and dirt.

Why it matters

Water that sits in fabric is the enemy. A properly proofed roof holds rain on the surface and lets it run off instead of soaking in, so the material dries far faster once the weather clears.

Everything else follows from that. Moisture and grime find it harder to cling to a proofed surface, which slows the rate at which algae, moss and lichen establish themselves, and less dirt trapped in the fibres means less of a sandpaper effect every time the roof flexes. Wear marks and thinning arrive later on a roof that has been kept proofed than on one that has not.

What proofing will not do is fix anything structural. It manages water at the outer surface and works with the membrane and the drainage behind it, so it belongs alongside those systems rather than in place of them.

When a roof needs redoing

You will see weather proofing mentioned in soft top restoration packages, detailing menus and inspection reports. Typical phrases include roof cleaned and weather proofed, recommend weather proofing after restoration or previous weather proofing worn off, roof soaking in water. It usually refers to fabric roofs such as mohair, rather than vinyl roofs, which are more often dressed than proofed.

Context

Weather proofing sits alongside cleaning, dyeing and leak diagnosis in the care of convertible roofs. The normal sequence is: inspect and identify any leaks or damage, deep clean to remove contamination, allow the roof to dry, then apply appropriate weather proofing products in thin, even coats. On modern multi-layer roofs, the hidden membrane and correct drainage do the main waterproofing work, while weather proofing improves surface behaviour and ease of maintenance. It will not cure leaks caused by failed membranes, split seams, blocked drains or perished seals, but it helps a sound roof stay cleaner, drier and looking better for longer. In our workshop the reproof is never the first step; the cleaning has to be thorough enough that the proofer goes onto a genuinely clean surface, otherwise you are sealing grit in.

Common mistakes

• Applying weather proofing products to a dirty or only lightly cleaned roof, trapping grit and contamination under the treatment.
• Expecting weather proofing alone to solve leaks caused by failed membranes, seams, drains or seals instead of investigating the underlying fault.
• Using generic water repellents or household waterproofers not designed for convertible roofs, which can leave patchy, shiny or sticky finishes.
• Assuming a roof that no longer beads water is beyond saving, when in many cases a proper clean followed by fresh weather proofing will restore performance and appearance.

Authored by Danny Argent. Reviewed by Gary Wray. Last updated 16 May 2026.